Nordic R-09, Installation And Service Manual, Page: 18 / 60

11-May-2021 Page 18 002512MAN-01
TABLE 12 - Volume of fluid per 100 ft. of pipe
Volume /100ft.
Type of Pipe Diameter I.gal gal L
Copper 1” 3.4 4.1 15.5
1-1/4” 5.3 6.4 24.2
1-1/2” 7.7 9.2 34.8
Rubber Hose 1” 3.2 3.9 14.8
Polyethylene 3/4” IPS SDR11 2.3 2.8 10.6
1” IPS SDR11 3.7 4.5 17.0
1-1/4” IPS SDR11 6.7 8.0 30.3
1-1/2” IPS SDR11 9.1 10.9 41.3
2” IPS SDR11 15.0 18.0 68.1
Other Item Volumes
Heat Exchanger Average 1.2 1.5 5.7
Purge Cart Tank See cart manual TBD
TABLE 11 - Antifreeze Percentages
BY VOLUME
Protection to: 10°F 15°F 20°F 25°F
Methanol 25% 21% 16% 10%
Propylene Glycol 38% 30% 22% 15%
Protection to: 10°F 15°F 20°F 25°F
Methanol 16.8% 13.6% 10% 6.3%
Propylene Glycol 30% 23.5% 18.3% 12.9%
BY WEIGHT
pressure before actual water pressure is put on the system .
Systems without an expansion tank will experience greater fluc-
tuations in pressure between the heating and cooling seasons,
causing pressure gauges to have different values as the loop
temperature changes. This fluctuation is normal since
expansion and contraction of the loop fluid must be handled by
the elasticity of the plastic loop.

Pressurize the loop to a static pressure of 45 psig . when
installing a system in the fall going into the heating season.

Pressurize the loop to a static pressure of 25 psig . when
installing a system in the spring or summer going into the
cooling season.
After operating the heat pump for a period of time, any
residual air in the system should be bled off and the static pres-
sure should be verified and adjusted if necessary. Add
additional water / antifreeze mix with the purge cart to bring the
pressure back to the original setting if required.
Pipe Insulation
All ground loop piping inside the structure (between the
structure entry point and the heat pump) should be insulated
with 3/8” thick closed cell pipe insulation to prevent condensa-
tion and dripping onto floors or walls.
Low Pressure Control Selection
The purpose of the low pressure control is prevent heat
exchanger freezing in the case of a flow problem.
Unlike other NORDIC model series, low pressure control
selection for open loop for the R/RH 09-24 is done manually,
with a wire jumper. For closed loops with antifreeze, make sure
a jumper is connected between LP1 and LP2 on the heat
pump’s terminal strip. This will cause the lower 55 psi low pres-
sure control to be selected, to allow a lower loop temperature
than would be appropriate for fresh water before tripping.
Although many different antifreeze solutions have been
employed in geothermal systems, the alcohols such as
methanol or ethanol have the most desirable characteristics for
groundloop applications. The overall heat transfer
characteristics of these fluids remain high although care must be
taken when handling pure alcohols since they are extremely
flammable. Once mixed in a typical 25% by volume ratio with
water the solution is not flammable. In situations where alcohols
are not allowed as a loop fluid due to local regulations then
propylene glycol is a non-toxic alternative which can be
substituted . Propylene glycol should only be used in cases
where alcohols are not permitted since the heat transfer
characteristics are less desirable and it becomes more viscous
at low temperatures, increasing pumping power.
The volume of fluid that your loop system holds can be
closely estimated by totaling the number of ft. of each size pipe
in the system and referencing the following table for
approximate volume per 100 ft.
When the volume of the loop has been calculated and the
appropriate amount of antifreeze is ready for addition by
referencing the table, drain the equivalent amount of water from
the flush cart or mixing barrel and replace it with the antifreeze.
When using alcohols, be sure to inject below the water
line to reduce initial volatility of the pure antifreeze. If the
loop is large it may be necessary to refill the tank with antifreeze
several times to get all the antifreeze into the loop. Pump the
loop for 5 to 10 minutes longer to ensure the remaining fluid has
been well mixed.
Initial Pressurization
At this point open all valves in the flow circuit and slowly
close off the supply and return flush cart valves in a manner that
leaves about 20-30 psig . on the system. If an air bladder
expansion tank is used it should be charged to the above
Adding Antifreeze Solution
In most mid and northern areas of the US and in all of
Canada it is necessary to condition the loop fluid by the addition
of some type of antifreeze solution so that it will not freeze
during operation in the winter months. This antifreeze is required
because the loop fluid will normally reach a low entering
temperature of 28°F to 32°F (-2°C to 0°C) and refrigerant
temperatures inside the heat pump’s heat exchanger may be as
low as 20°F (11°C) cooler. See following table for details of
freeze protection provided by different concentrations.
WARNING: Add enough antifreeze to allow
for a temperature 20°F (11°C) lower than the
expected lowest loop fluid temperature
entering the heat pump. Insufficient anti-
freeze concentration could cause the heat
exchanger to freeze and rupture, voiding the
warranty.